In order to find out about the deaths of Peter and Paul, we have to look outside the New Testament. A number of letters and other literary works were written within the Christian community of the First Century, but only twenty-seven made it into the New Testament. Books which did not make it into the New Testament are known as "Apocrypha." Among the New Testament Apocrypha is a book entitled "The Acts of the Holy Apostles Peter and Paul." In this book we find a description of the deaths of Peter and Paul. Toward the end we find Peter and Paul in front of Nero, and we pick up the story there:
"Both Peter and Paul were led away from the presence of Nero. And Paul was beheaded on the Ostesian road. And Peter, having come to the cross, said: ‘Since my Lord Jesus Christ, who came down from the heaven upon the earth, was raised upon the cross upright, and He was deigned to call to heaven me, who am of the earth, my cross ought to be fixed head down most, so as to direct my feet towards heaven; for I am not worthy to be crucified like my Lord.’ Then having reversed the cross, they nailed his feet up."
So, Peter was crucified upside down and Paul was beheaded by Nero. Or were they? Earlier in the story we find Peter and Paul in front of Nero with a magician named Simon. To make a long story short, Simon claimed to be the son of God. Nero was inclined to believe Simon, and so Peter and Simon engage in a discussion of whether Simon or Jesus was the son of God. Finally Simon says that he will prove he is the son of God. He stands on a high place and begins to fly. Nero looks at Peter and says (and I paraphrase), if you can do better than that I will believe in Jesus. Peter closes his eyes and prays "In the name of Jesus, I command the angels of Satan who are holding Simon up to be removed." Simon came crashing down and died. At that point Nero orders the death of Peter and Paul.
So, did Simon really fly? We would all say no. So, was Peter crucified upside down and Paul beheaded? Maybe. It is easy to see why this book was not included in the New Testament because people do not fly, but the death stories may be true.
The Apocrypha books were not excluded from the New Testament because they were total lies but because they were not inspired and had some falsehoods. Many New Testament scholars believe that the New Testament Apocrypha probably contain truthful accounts scattered here and there amidst the fabricated stories. But which are truthful and which are made up? In this book it is obvious that Simon’s flight was the product of someone’s imagination. But Peter crucified upside down and Paul beheaded? That could have happened. And it is easy to believe that Peter would have made the request to be crucified upside down for the reason he did.
Therefore the deaths of Peter and Paul are said to be "according to tradition." This means that we do not know for certain if it happened that way, but it is the best we have to go on.
